Dry transfer image systems with non-light sensitive frangible layer

ABSTRACT

A dry system for forming and transferring images is provided. The system comprises a photoactive component comprising a tacky photohardenable layer on a selected carrier sheet and a transfer component comprising a frangible color layer on a selected carrier sheet. The two components are disposed with their photohardenable and color layers in air-free contact with one another and then subjected to irradiation with actinic radiation in accordance with a selected image pattern so as to cause selected portions of the photohardenable layer to harden and fuse to confronting portions of the color layer. Then the two components are separated whereby the fused portions of the color layer are separated from its carrier sheet and transferred to the photoactive component. Thereafter the color layer remaining on the transferable component is coated with a pressure-sensitive adhesive. Finally, the transferable component is positioned with its adhesive coating engaging a receptor substrate and the rear side of its carrier sheet is rubbed hard or burnished with a suitable implement so as to cause the remaining image-defining portions of the color layer to separate from its carrier sheet and adhere to the receptor substrate.

This invention relates to transfer imaging systems and more particularlyto a new method and materials for forming transferable images.

One primary object of this invention is to provide a new and versatilesystem for rapidly producing transferable images without the need forexpensive and complex specialized equipment. Another primary object isto provide a transfer imaging system for use in the graphic arts fieldwhich is capable of inexpensively producing letters or numerals in awide variety of colors, sizes and styles that can be transferred to aselected substrate. A further primary object is to provide a versatiletransfer imaging system which enables the user to selectively vary thecolor, style and size of the transferable images which are produced.

A more specific object is to provide a system for forming transferableimages based on the selective adhesion of images made by exposing aphotoactive layer to light through a selected master.

Another specific object is to provide a method and materials for formingtransferable images where the size and form of the image is determinedby exposure of a photoactive layer to light through an appropriatepositive or negative master and the color of the image is determined byuse of an appropriate image-transferring color sheet in contact with thephotoactive layer.

The foregoing objects are achieved by a system which comprises two basiccomponents: (1) a photoactive component in the form of a transparentcarrier film with a photoactive coating which is photopolymerizable orphotohardenable; and (2) a transferable component in the form of acarrier film with a frangible, transferable layer which may contain acolorant. The two components are placed together as a sandwich so thatthe photoactive coating contacts the frangible coating. The transferableimages are formed by (A) exposing the dual component sandwich to lightvia a suitable image-defining mask whereby selected portions of thephotoactive coating photopolymerize and form a relatively strong bondwith confronting portions of the frangible layer and (B) separating thetwo components whereby each portion of the frangible layer confrontingan illuminated portion of the photoactive coating pulls away from itscarrier film due to adhesion with the photopolymerized portion of thephotoactive coating. The portion of the frangible layer remaining on itscarrier sheet defines the transferable image which is thereafterreleased and transferred to a selected substrate, e.g. to art work.Other features and many of the attendant advantages of the invention aredisclosed in the following detailed description which sets forth apreferred embodiment and is to be considered together with theaccompanying drawing wherein:

FIGS. 1 and 2 illustrate the photoactive and transferable componentsrespectively;

FIG. 3 illustrates how the components of FIGS. 1 and 2 are laminatedtogether to form an integrated sandwich structure; and

FIGS. 4A-4E illustrate how a transferable image is formed andtransferred using the sandwich structure of FIG. 3.

In the several views like numerals and letters identify like parts,unless otherwise indicated.

Referring now to FIG. 1, the photoactive component A essentiallycomprises a clear optically transmissive carrier sheet or film 2 whichhas been overcoated on one side with a layer of photopolymerizable orphotohardenable composition 4.

The terms photopolymerizable and "photohardenable" are used herein torefer to systems in which the molecular weight of at least one componentof the photoactive layer or coating is increased by exposure to actinicradiation and where the proportional amount of such component issufficient for the radiation-induced increase in its molecular weight tocause a change in the rheological and thermal behavior of the exposedareas of the coating. Among suitable photopolymerizable systems whichmay form the photoactive coating in whole or in part are: (1) those inwhich a photopolymerizable monomer is present alone or in combinationwith a suitable binder or (2) those in which a photopolymerizable group,e.g. a vinyl monomer, is attached to a polymer backbone and which onexposure to radiation will crosslink by reaction with a similar group orother reactive sites on adjacent polymer chains. The second group ofphotopolymerizable systems may or may not include a compatible binder.In both groups of photopolymerizable systems the compatible binder maybut need not be a polymer. The photopolymerizable component may beinherently light sensitive or it may be sensitized forphotopolymerization by including a photo-initiator or sensitizer in thephotoactive composition. In any event the photoactive layer is made sothat it is tacky and can adhere to the transferable component Bdescribed hereinafter. Typically, the tackiness of the photoactive layer4 is achieved by depositing the photopolymerizable composition onto thefilm 2 from a solution in a volatile solvent.

Preferably, the photoactive layer has a thickness of about 0.010 inch,but satisfactory results also may be achieved if the photoactive layerhas a thickness as little as about 0.005 inch, or as great as about0.025 inch. The film 2 has preferably a thickness in the range fromabout 0.001 to about 0.020 inch. However, other thicknesses also may beused. The photoactive layer 4 may but need not have some capability oftransmitting light (including the light used to activate it) since thesystem does not require the transferable component to absorb or beactivated by light energy. Preferably, however, the photoactive layerhas a relatively low transmittance for light of the frequency requiredto activate the photopolymerizable component and a relatively hightransmittance for light of all other frequencies. In the preferredembodiment of the invention, the carrier sheet 2 may be a polyethyleneterephthalate, e.g. of the type made and sold by E. I. duPont de NemeursCompany under the trademark "MYLAR" and the photoactive composition 4comprises a mixture of an acrylic monomer and an acrylic polymer as abinder for the monomer, with the monomer sensitized forphoto-polymerization by a photo-initiator such as phenanthrene quinone.

The transferable component B essentially comprises a carrier sheet orfilm 6 which is overcoated on one side with a substantially uniform andnormally stable but frangible transferable layer 8. The sheet 6 may butneed not be transparent to visible light and/or light of the frequencyrequired to activate layer 4 and may be a film such as is used as thecarrier sheet for the photoactive component A. Carrier sheet 6preferably has a thickness in the range of about 0.001 to about 0.030inch.

The frangible, transferable layer 8 preferably is formed with athickness of about 0.005 inch, but the thickness could be smaller orgreater. Preferably its thickness is not less than about 0.0005 and notgreater than about 0.010 inch. The frangible layer 8 may be of widelydifferent compositions, but preferably it comprises one or more polymeror polymeric binders in admixture with one or more waxes. Additionally,the layer 8 may include a solid or liquid plasticizer, a pigment or dyeto impart color if the layer otherwise would be colorless or ofundesired color, and an opacifier if needed. Still other ingredientssuch as a temperature stabilizing agent may be included in the frangiblelayer.

In the preferred embodiment of the invention the carrier sheet 6 isclear transparent polyethylene terephthalate film and the frangiblelayer 8 has a composition as shown in composition 7 of Table II.

Referring now to FIG. 3, the photoactive component A and thetransferable component B are preformed and then are brought together sothat the tacky photoactive layer 4 intimately engages and holds onto thefrangible layer 8. This is achieved by subjecting the mutually engagingsheets to a pressure which is substantially uniform along their entireareas. Preferably, the two sheets are laminated together by compressingthem between a pair of platens or by passing them between a pair ofpressure rollers.

The formation and transfer of an image using the dual component sandwichof FIG. 3 is achieved in accordance with the procedure illustrated inFIGS. 4A-4E. A mask 10 which is formed with opaque and transparent areas11 and 12 respectively so as to define a predetermined positive ornegative master image is disposed between the sheets and a selectedlight source (not shown) which is arranged to uniformly illuminate themask with actinic light. In FIG. 4A the illuminating radiation isrepresented schematically by the arrows 14. The indirect light energy isblocked by the opaque areas 11 of the mask and transmitted by thetransparent areas 12 of the mask. In FIG. 4A, the arrows 16 representthe light energy which is passed by the transparent areas of the maskand impinges on the transparent substrate 2 of the photoactive componentA. The light passes through the transparent carrier sheet 2 into thephotoactive composition 4, with the area of the latter composition whichis subjected to light conforming in configuration to the area 12 of themask which is transparent to the light energy. The sandwich isilluminated for a period of time sufficient to cause the irradiatedphotopolymerizable component(s) in the layer 4 to undergophotopolymerization. The irradiated photopolymerizable component isconverted to a substantially hard, non-tacky polymer which is securelybonded to the adjacent portion of the frangible layer 8. The remainingarea of the photoactive composition 4 remains tacky due to the fact thatits photopolymerizable component remains unchanged.

Thereafter, as shown in FIG. 4B, the photoactive component A is pulledaway from the transferable component B. When this occurs, that portionof the transferable layer 8 which was in confronting relation with theportion of the photoactive composition 4 which underwentphotopolymerization, is pulled away from the carrier sheet 6 as adiscrete section 8A which is joined to the photoactive composition 4.The portion 8A breaks away from the remaining portion of thetransferable layer 8 so as to leave a cavity 9 in the frangible layer 8which conforms in configuration to the configuration of the transparentportion 12 of mask 10. At this point the sections 8B of the frangiblelayer 8 which remain attached to the carrier sheet 6 define a positiveimage of the opaque areas of mask 10. A further significant feature isthat the portion of the photoactive layer 4 which was not exposed tolight tends to separate from itself and adhere to the layer 8 when thephotoactive component A and the transferable component B are separatedfrom one another so that a thin tacky film 7 of the photoactive layer 4overlies the sections 8B of layer 8.

Following separation of the components A and B, a thin layer 18 of atranslucent or transparent pressure-sensitive adhesive is applied overthe image-defining sections 8B remaining on the carrier sheet 6 as shownin FIG. 4C. This adhesive layer preferably consists of one or more waxesof suitable consistency and may be applied from a solution thereof in avolatile solvent or as molten layer. The adhesive layer 18 may beapplied by spraying, dipping, roller-coating or other suitable techniqueknown to persons skilled in the art. Next, as shown in FIG. 4C, thetransferable component B is exposed to actinic radiation (represented byarrows 19) so as to photopolymerize and set the unreacted tackyphotoactive material 7 on the image-defining sections 8B. The resultingproduct is then ready for use. Accordingly, as shown in FIG. 4D, theadhesive composition 18 on the color layer 8 is brought into contactwith an image receptor or image-receiving substrate 20 and pressedagainst the latter hard enough for the adhesive to adhere to thesubstrate. Transfer of selected images, e.g. selected ones of formedletters or numerals, may be effected by rubbing the rear side of carriersheet 6 with a suitable tool in the manner described in U.S. Pat. No.3,013,917. Thereafter, as seen in FIG. 4E, the carrier sheet 6 is peeledaway from the substrate and, as this occurs, the transferable layersections 8B transfer onto the substrate 20 as a result of adhesion ofadhesive layer 18. The portions of the adhesive composition 18 which donot overlie the image-defining sections 8B tend to remain attached tothe carrier sheet 6, after the latter is pulled away from the substrate20, as illustrated at 8C. However, if the adhesive is clear ortranslucent, it is immaterial whether or not the portions 8C end up onthe carrier sheet 6 or substrate 20.

The following requirements must be met for satisfactory image formationand image transfer:

(1) The illuminating radiation must comprise radiation in the activatingwavelength band of the photopolymerizable component, i.e., the radiationmust be actinic;

(2) The adhesion between the photopolymer (i.e., the polymer produced byphotochemical reaction) and its carrier film must be equal to or greaterthan the adhesion between the frangible layer and its own carrier film;

(3) The adhesion between the frangible layer and its carrier film shouldbe less than the bond formed between the frangible layer and thephotopolymer;

(4) The bond formed between the adhesive coating and the frangible layerand the bond formed between the adhesive coating and the substrate orartwork to which transfer is to be made must be greater than theadhesion between the frangible layer and its carrier film; and

(5) When components A and B are separated, the frangible layer must pullaway completely from its carrier sheet in those areas where it confrontsthe photopolymer.

As used herein, the term "frangible coating" or "frangible layer"describes a coating or layer which is mechanically disruptable intoportions of selected size that are separable from contiguous portionsalong sharply and clearly defined lines.

The selective adhesion which is required to leave a transferable imageon the carrier sheet 6 is controlled by the compositions of thephotoactive component A and the frangible transferable component B, andthe degree of irradiation by actinic light. As used herein, the terms"actinic light" and "actinic radiation" means light or radiation whichcomprises or consists of energy at wavelengths at which the energy iscapable of initiating a photochemical polymerization reaction. Sincemost of the photopolymerizable materials preferred for this inventiongenerally exhibit their maximum sensitivity in the near-ultravioletregion, the light source should furnish an effective amount of suchradiation. The mask through which the photoactive component A is exposedmay be a line or half-tone negative or positive trnasparency and thepositive or negative image or images defined by the mask may be letters,numbers, punctuation marks, or other designs.

The sheet 2 is preferably transparent but it may be translucent providedits light transmitting power is sufficiently great to permit thephotoactive layer to be irradiated with a sharp image and intenselyenough to photopolymerize. A number of different materials may be usedas the carrier sheet 2 of the photoactive component A. By way of examplebut not limitation, the carrier sheet 2 also may be made of materialsfrom the following list: cellophane, coated cellophane, celluloseacetate butyrate, cellulose acetate, polyvinyl chloride, polyvinylacetate, polystyrene, polymers of C₂ to C₄ mono-olefins (polyethylene,polypropylene, etc.), and copolymers thereof, e.g. polyvinylacetate/chloride. Other materials that may be used may be selected fromthe carrier sheets listed in U.S. Pat. No. 3,432,376.

A number of different materials also can be used as the carrier sheet 6of the transferable component B. Thus, by way of example but notlimitation, the materials mentioned above as suitable for the carriersheet 2 may also be used for the carrier sheet 6. Since it need not betransparent, colored cellulose acetate or colored Mylar® may be used asthe carrier sheet 6 for component B. By way of further example, carriersheet 6 also may be made of paper, polyvinyl acetate, vinylidenechloride, metal foil, glassine or glass. Still other materials that maybe used for carrier sheet 6 may be selected from the carrier sheetmaterials listed in U.S. Pat. No. 3,510,385.

The photoactive coating preferably comprises a mixture of polyn-butylmethacrylate polymer as a binder and 1,3-butylene glycol dimethacrylatemonomer as the photohardenable material, with phenanthrene quinone asthe photocatalyst or photo-initiator. However, other materials may beused in their stead. Thus, for example, the foregoing polymerconstitutuent may be replaced by poly methyl methacrylate or poly ethylacrylate while the monomer may be replaced by ethylene glycoldimethylacrylate or diethylene glycol diacrylate. Further, by way ofexample, benzoin, benzoin ethers, Michelers ketone, and benzophenone maybe used in place of phenanthrene quinone. For further descriptions ofphotohardenable materials and compatible binders and photocatalysts(i.e., photosensitizors or photo-initiators) that may be used therewith,reference is made to U.S. Pat. Nos. 3,649,268, 3,620,726 and 3,615,435.Still other polymers, photoactive monomers and photocatalysts known topersons skilled in the art may be used in practicing this invention.

For the purpose of this invention the photoactive coating should beformulated as follows on a weight percent basis:

    ______________________________________                                        Photoactive monomer    20-60%                                                 (or polymer with pendant                                                      photopolymerizable group)                                                     Polymer binder         40-80%                                                 Photo-initiator        as required                                            ______________________________________                                    

Preferably, but not necessarily, the photo-initiator does not exceedabout 3.0% by weight and constitutes between about 0.2% and 3.0% of thephotoactive coating.

The photoactive coating preferably is formed by depositing the foregoingmixture from solution in a suitable solvent. Accordingly, the foregoingmixture is combined with an amount of a volatile solvent such asmethylene chloride which is sufficient to effect dissolution and form aspreadable liquid. Typically the liquid comprises enough solvent to forma 20-40% total solids solution. The liquid is coated onto the carriersheet as a uniform film, whereupon the solvent evaporates and leaves atacky photoactive coating on the carrier sheet.

Table I illustrates a number of formulations on a weight percent basiswhich have been devised to form photoactive components according to thisinvention. In each case the photoactive layer was deposited fromsolution onto a clear transparent carrier sheet made of polyethyleneterephthalate and having a thickness of 0.001 inch.

                                      TABLE I                                     __________________________________________________________________________            Formulation No.                                                       Component                                                                             1   2   5   7   10  13  14  17  26                                    __________________________________________________________________________    Poly n-butyl-                                                                         10.8                                                                              10.8                                                                              13.1                                                                              10.8                                                                              10.8                                                                              22.1                                                                              17.5                                                                              10.6                                                                              --                                    methacrylate                                                                  resin (Elva-                                                                  cite 2044)                                                                    1,3 Butylene                                                                          8.1 8.1 7.9 8.1 8.1 8.3 8.1 8.0 8.1                                   glycol di-                                                                    methacrylate                                                                  (SR-297)                                                                      pyrogenic                                                                             --  0.3 --  --  --  --  --  1.3 --                                    colloidal                                                                     silica (Cab-                                                                  O-Sil M5)                                                                     Phenanthrene                                                                          0.3 0.3 0.3 --  --  --  --  --  --                                    quinone                                                                       Benzoin iso-                                                                          --  --  --  0.3 --  --  --  --  --                                    propyl ether                                                                  Benzoin iso-                                                                          --  --  --  --  0.3 0.3 0.3 0.3 --                                    butyl ether                                                                   (Vicure 10)                                                                   Acrylic --  --  --  --  --  --  --  --  10.8                                  resin (Car-                                                                   boset 525)                                                                    Methylene                                                                             80.8                                                                              80.5                                                                              78.7                                                                              80.8                                                                              80.8                                                                              --  74.1                                                                              79.8                                                                              80.8                                  chloride                                                                      Total   100.0                                                                             100.0                                                                             100.0                                                                             100.0                                                                             100.0                                                                             100.0                                                                             100.0                                                                             100.0                                                                             100.0                                 __________________________________________________________________________     Elvacite 2044 is a product of E.I. DuPont de Nemeurs Co., Polymer Product     Division).                                                                    SR-297 is a product of Sartomer Co.                                           Cab-O-Sil M5 is a product of Cabot Corporation.                               Vicure 10 is a product of Stauffer Chemical Co.                               Carboset 525 is a product of B.F. Goodrich Chemical Co., and is believed      to be an acrylic polymer with an average molecular weight of about            260,000.                                                                 

The essential requirement of the coating 8 is that it be flexible andcomply with the above-described requirements for satisfactory imageformation and transfer. The coating 8 preferably consists of a mixtureof one or more thermoplastic film-forming binders and one or moresynthetic or natural waxes, but it may comprise other componentsinstead.

The frangible layer of the transferable component B may have inherentopacity or color which is adequate for the purposes of the invention. Ifit does not, an opacifying agent or colorant is added to it to assurethat the image which is produced and transferred is of suitable quality.A suitable solid or liquid plasticizer also may be added to control thedisruptability of the coating. In the preferred types of flexiblecoatings, the amounts of film-forming binders and waxes (which will varyaccording to the specific binders and waxes employed and whether or notplasticizers or fillers are used) are controlled so as to impart thedesired strength, flexibility, disruptability and adhesiveness to thecolor coat. Animal, vegetable and mineral waxes and waxy materials maybe used in forming the flexible coating 8, including but not limited tomicrocrystalline wax, spermaceti wax, carnauba wax, beeswax, castor wax,polythene wax, candelilla wax, monton wax, petroleum waxes, paraffinwaxes, paraffinic-naphthenic waxes, polyethylene waxes, Fischer-Tropschwaxes, fatty acids and their derivatives such as fatty acid esters ofpolyols such as polyethylene glycols and polypropylene glycols and fattyalcohol ethers of polyols such as polyethylene glycols and polypropyleneglycols, and mixtures thereof. In addition to nitrocellulose, among thefilm-forming resins that may be used as the binder component of thefrangible layer 8 are ethyl cellulose, cellulose acetate-butyrate,polyvinyl acetate, polystyrene, acrylonitrile-butadiene copolymer,styrene-butadiene copolymer, acrylic resins such as methyl methacrylateand ethyl acrylate, ethyl methacrylate, propyl methacrylate, and butylmethacrylate, polychloroprene rubbers, polyvinyl butyral, and alsocopolymers and mixtures thereof. The relative proportions of wax andbinder may vary within relatively wide limits depending upon the exactmaterials used. Various plasticizers and solvents known to personsskilled in the art also may be used in frangible layer 8. By way ofexample but not limitation, the coating 8 may include one or more of theester-type plasticizers listed in U.S. Pat. No. 3,645,204.

A variety of particulate or dye-type colorants may be used informulating the transferable frangible coating. The colorants may bepigments, dyes, or lakes. By way of example, one or more of thefollowing pigments may be used: zinc yellow, bronze and iron blue, brownred haematite, red lake C, and carbon black. Still other colorants areC.I. Vat Yellow 1, C.I. Pigment Red 122, C.I. Pigment Blue, C.I. PigmentBlack 1 and C.I. Pigment Yellow 12. See also the colorants specified inU.S. Pat. Nos. 3,615,435 and 3,620,726. Instead of or in addition to acolorant, other materials also may be incorporated into the frangiblelayer, e.g. glass beads, magnetic materials such as magnetic iron andchromium oxides, and electrical or heat conducting and hydrophobic orhydrophilic materials.

The ingredients which make up the frangible layer are coated onto thecarrier sheet 6 from a solution in a suitable volatile solvent. Thesolvents that may be used may be selected (in accordance with the binderemployed) from the following group: methyl ethyl ketone, toluene, methylisobutyl ketone, xylene, methanol, ethyl alcohol, heptane, ethylacetate, butyl acetate, methylene chloride, methylene dichloride,dichloroethyl ether, trichloroethylene and benzene (the selected solventfor the binder may also serve as a solvent for the wax or waxy componentof layer 6). Preferably the layer is coated on the carrier sheet from a20-30% by weight total solids solution.

Tables II, III and IV illustrate various color coat formulations (on aweight percent basis) used to form the transferable component B. TableII shows typical formulations based on nitricellulose which have beenused to coat a polyethylene terephthalate carrier sheet with a thicknessof 0.001 inch, Table III shows typical formulations of coatings based onan alcohol soluble butyrate which have been used to coat a polyethyleneterephthalate carrier sheet with a thickness of 0.001 inch, and Table IVshows typical coatings based on polyvinyl butyral which have been usedto coat a polyethylene terephthalate carrier sheet measuring 0.001 inchthick. In each case the uncoated carrier sheet was clear andtransparent. The abbreviations G and E stand for "good" and "excellent"respectively. The designation "P.A." followed by a numeral identifiesone of the photoactive compositions of Table I.

The image quality of the color coats of Tables II and IV were determinedwith respect to photoactive components using photoactive layerFormulation No. 7 of Table I.

                  TABLE II                                                        ______________________________________                                                  Formulation No.                                                     Component   7       10      11    12    13                                    ______________________________________                                        Nitrocel-   18.4    18.4    18.4  18.4  18.4                                  lose, RS 1/4                                                                  sec., viscos-                                                                 ity 4.7                                                                       Glycowax    9.5     14.0    21.0  19.8  11.7                                  S-932                                                                         Flexowax C  4.7     --      --    --    --                                    Castor Oil  6.7     7.0     --    --    7.0                                   AA, USP                                                                       Paracin 9   --      --      --    1.2   2.3                                   Color Pigment                                                                             47.2*   47.2*   47.2**                                                                              47.2**                                                                              47.2**                                Titanium    13.5    13.4    13.4  13.4  13.4                                  Dioxide                                                                       Total Solids                                                                              100.0   100.0   100.0 100.0 100.0                                 Solvent *** 316     316     316   316   316                                   Solvent as %                                                                              24.0    24.0    24.0  24.0  24.0                                  of total                                                                      solids                                                                        Image       G       G       G     G     G                                     Definition                                                                    Overall Qual-                                                                             G       G       G     G     E                                     ity of Image                                                                  Completeness                                                                              100%    100%    100%  100%  100%                                  of Letters                                                                    Transfer                                                                      Completeness                                                                              75%+    75%+    50%+  75%+  95%+                                  of Letters                                                                    Background                                                                    Retention                                                                     ______________________________________                                         *Monastral Blue BF (duPont)                                                   **Mapico Red 297 (Columbian Carbon)                                           ***The solvent comprised by weight 3 parts toluene, 2 parts butyl acetate     and 1 part ethyl acetate.                                                

                  TABLE III                                                       ______________________________________                                                      Formulation No.                                                 Component       23        24        42                                        ______________________________________                                        ASB             18.5      10.2      7.8                                       ZKMA 0251       74.1      81.6      30.8                                      Ketone Resin                                                                  Polyglycol      --        --        23.0                                      E 1000                                                                        Pigment         7.4       8.2       26.9                                      Titanium        --        --        11.5                                      Dioxide                                                                       Total Solids    100.0     100.0     100.0                                     Solvent*        259       286       231                                       Solvent % of    27.9      25.9      30.2                                      total solids                                                                  Quality of                                                                    Image as com-                                                                 pared to:                                                                     P.A. 10         G-        G+        --                                        P.A. 7          --        --        G                                         P.A. 17         --        --        E                                         ______________________________________                                         *The solvent was ethanol (200P).                                         

                  TABLE IV                                                        ______________________________________                                                        Formulation No.                                               Component         23A         24A                                             ______________________________________                                        Butvar            4.5         --                                              (B-76-1)                                                                      Beckacite         44.7        46.7                                            43-111                                                                        Stearic Acid      --          0.1                                             Color             25.4        26.6                                            Pigment*                                                                      Titanium          25.4        26.6                                            Dioxide                                                                       Total Solids      100.0       100.0                                           Solvent**         402.0       421.0                                           Solvent as %      19.9%       19.2%                                           of solids                                                                     Definition of     G           G                                               Image                                                                         Overall Qual-     G           E                                               ity of Image                                                                  Completeness      100%        100%                                            of letters                                                                    transfer                                                                      Completeness      95%+        100%                                            of background                                                                 retention                                                                     ______________________________________                                         *Mapico Red 297                                                               **The solvent was methylethyl ketone.                                    

Glycowax S-932 is a wax product of Glyco Products, Co.; Flexowax C is awax product of Glyco Products, Co.; Paracin 9 is a wax product of BakerCaster Oil Co.; ASB is a commercially available Eastman Chemical Co.,alcohol soluble butyrate resin; ZKMA 0251 is a product of Union CarbideCo.; Polyglycol E 100 is a plasticizer material made by Dow ChemicalCo.; Butvar (B-76-1) identifies a polyvinyl butyral-resin made byMonsanto Co.; and Beckacite 43-111 is a maleic modified rosin ester.

The adhesive composition 18 preferably is formulated so that itsadherence to the substrate 20 to which the formed images are transferredis not so great as to prevent the transferred images from being peeledoff of or erased from the substrate. While a heat or solvent activatedadhesive may be used, it is preferred that the adhesive coating 18 be ofthe pressure sensitive variety. Also in the preferred mode of practicingthe invention, it is preferred that the adhesive coating be clear ortranslucent and colorless or white, so that the sharpness of thetransferred images will not be reduced by the appearance of any of theadhesive which transfers to the substrate 20 close to but outside of theedge boundaries of the images. It has been determined that adhesives areavailable which satisfy the needs of this invention. Two commerciallyavailable pressure-sensitive adhesive wax compositions which have beenused with equal success in the practice of this invention are BB9adhesive produced by Daige Products, Inc., and ARTWAX® available fromPortage Products, Inc. Still other suitable pressure-sensitive waxcompositions are known to persons skilled in the art. The adhesivecomposition may be of the type that comprises one or more waxes and anelastomer binder proportioned so as to achieve the desired adhesiveproperties, but other adhesive compositions also may be used. Theadhesive preferably is applied as a hot melt but it may be dissolved ina suitable volatile solvent and applied as a liquid coating. A preferredadhesive composition which can be applied as a hot melt comprises amixture of a wax or waxes and a natural or synthetic elastomer with theweight ratio of wax to elastomer being in the range of from about 95/5to about 85/15. By way of example, the wax may be microcrystalline wax,and the elastomer may be polyisobutylene. The same adhesive may bedissolved in a volatile solvent such as naphtha so that it can beapplied as a liquid at room temperature. The adhesive may also include atackifying resin and/or a plasticizer. By way of example, the elastomeralso may be a member of the group consisting of (a) natural rubber, (b)a synthetic rubber from the class consisting of styrene-butadienecopolymers, butadiene-acrylonitrile copolymer, polychloroprene andpolyisoprene, and (c) other polymers and copolymers known to personsskilled in the art (see U.S. Pat. No. 3,623,944, column 8, lines 21-29).Other pressure sensitive adhesives which persons skilled in the art mayrecognize as suitable for use in the practice of this invention aredisclosed by U.S. Pat. Nos. 3,472,719, 3,532,574, 3,276,933, 3,013,917,3,519,456 and 3,510,385. Persons skilled in the art also will appreciatethat available formulations of pressure-sensitive adhesives may berequired to be adjusted, e.g. by dilution, in order to achieve thedegree of adhesion, fluidity and tackiness required for this invention.As is believed obvious, many of the waxes or waxy-materials, resinbinders and solvents employed in formulating the color coat 8 also maybe used in formulating the adhesive 18.

The reason for irradiating the transferable component B after it iscoated with the adhesive coating 18 is that the photohardenablecomponent is usually anaerobic, i.e., it will harden under the influenceof actinic radiation only if it is not exposed to air. The lattercondition is achieved by applying the adhesive composition over thefrangible coating after it is separated from the photoactive componentA.

As noted above, the frangible layer 8 need not combine a binder and awax but instead may have some other composition. By way of example, thefrangible layer may consist by weight of 14.6% shellac, 7.2% 1/2 sec.nitrocellulose, 39.1% calcium carbonate, and 39.1% titanium dioxide,applied as a 20% solids solution in a mixture of methanol and methylethyl ketone. As a further example, the frangible layer 8 may consist of15 wt% Acryloid B-44 acrylic resin (a product of Rohm & Haas Co.) and 85wt.% calcium carbonate and titanium dioxide in a 9:1 ratio, applied as a20% solids solution in toluene. The calcium carbonate and titaniumdioxide serve to impart color to the coatings; also due to their highconcentration, they help make the layer 8 frangible. Frangible layersmade with the foregoing compositions may be applied to sheet materialsof the type described above with respect to the carrier sheet 6, andtransferable components embodying such layers are effective in producingand transferring images as provided by this invention. Still othercompositions may be used in producing frangible layers suitable for thepurposes of this invention.

Suitable sources of energy in the ultra-violet and near-ultra-violetregions of the spectrum are well known in the art, as disclosed by U.S.Pat. No. 3,639,123. In the practice of this invention a preferredexposure apparatus is Nu Arc carbon arc light source model SPN 20A,which uses a Natural High Intensity Photo 76, Catalog No. L8593, carbonarc available from Union Carbide Corporation, Carbon Products Division.Exposure times of 2 minutes with the photoactive component located 10inches from the face of the carbon arc light source have been found togive consistently good images, but satisfactory results also have beenachieved at the same distance with exposure times ranging from 15seconds to 4 minutes.

As a modification of the invention, it is contemplated that thetransferable component carrier sheet 6 may be coated with a releaselayer disposed between it and the frangible coat 8 to facilitateseparation of the formed images 8B to the substrate 20. The releaselayer may be heat sensitive as contemplated by U.S. Pat. Nos. 3,516,842and 3,340,121, but preferably only where the adhesive 18 is of theheat-activated variety. Alternatively the release layer may comprise adry release coating of a selected silicone or quilon, as disclosed byU.S. Pat. No. 3,635,746.

Another modification of the invention consists of not initiallycombining the photoactive component A with the transferable component B,but instead covering the tacky photoactive coating 4 with a suitablerelease paper or film that will not adhere or else will only adherelightly to the tacky coating. This enables the photoactive component tobe packaged and shipped separately from the component and enables theuser to selectively combine the photoactive component with transferablecomponents of different colors.

A further modification of this invention is not to apply the adhesivecoating 18 to the transferable component B until after the latter hasbeen irradiated to harden the thin film of photo-hardenable materialwhich adhered to it on its separation from the photoactive component A.Instead the separated component B may be covered with a suitable releasesheet which isolates it from the air and also will not bond to theresidual photoactive film when the color component B is irradiated forthe second time. The release sheet may be retained with the component Bto protect the latter until it is desired to transfer the formedletters, at which time the release sheet is peeled away, a suitableadhesive is coated over the formed image sections 8B of the transferablecomponent, and the formed image sections are transferred to a suitablesubstrate by rubbing the rear side of the carrier sheet with a suitableimplement as described above.

Still another modification involves transferring the image definingsections 8B remaining on the carrier sheet 6 to a receptor surface orsubstrate without having to apply an adhesive to either the substrate orthe image defining portions 8B remaining on the carrier sheet material.This modification involves transferring the formed images to a lighttransmitting substrate or receptor member, e.g., a transparent plasticsheet. This modification comprises carrying out the steps illustrated inFIGS. 4A and 4B, after which the transferable component B carrying theformed images 8B is laid up against the transparent substrate andactinic radiation is directed through the transparent substrate at theimage defining sections 8B, such that the thin film 7 of tacky unreactedphoto-active materials adheres to the receptor surface and polymerizesto form a strong adherent bond with the receptive surface. Thereafterthe substrate or carrier sheet 6 is stripped away, leaving the formedimages 8B attached to the transparent substrate. This modification issuitable for forming signs. The receptor substrate may be translucentand/or colored, the only requirement being that it be capable oftransmitting actinic radiation.

Still other modifications will be obvious to persons skilled in the art.

What is claimed is:
 1. A dry image reproduction laminate comprising aphotoactive component and a transferable component,said photoactivecomponent comprising a first support and a single layer of an unexposedphotopolymerizable material on said first support, said first supportbeing capable of transmitting radiant energy at a wavelength at whichsaid energy is capable of initiating a photochemical hardening reactionin said photopolymerizable material, said layer of photopolymerizablematerial on said first support being tacky, said transferable componentcomprising a second support, and an adherent colored layer of afrangible non-photopolymerizable material on said second support, saidfrangible non-photopolymerizable layer comprising at least one polymerbinder and at least one wax, said layers of photopolymerizable andfrangible non-photopolymerizable materials being in confronting andadhering relation to one another, said layer of unexposedphotopolymerizable material having an adhesion to said first supportwhich is greater than the adhesion between said layer of frangiblenon-photopolymerizable material and said second support, and saidphotopolymerizable material being capable upon hardening of bonding tosaid frangible non-photopolymerizable material with an adhesive strengthgreater than the adhesion between said frangible non-photopolymerizablematerial and said second support.
 2. An image reproduction laminateaccording to claim 1 wherein said photopolymerizable layer contains anorganic polymer binder.
 3. An image reproduction laminate according toclaim 1 wherein said photopolymerizable material comprises an organicpolymer binder and a photopolymerizable monomer.
 4. An imagereproduction laminate according to claim 3 wherein said second supportis translucent or transparent.
 5. An image reproduction laminateaccording to claim 1 wherein said first support is a plastic film.
 6. Animage reproduction laminate according to claim 1 wherein said firstsupport is a transparent plastic film material.
 7. An image reproductionlaminate according to claim 1 wherein said frangiblenon-photopolymerizable material comprises a colorant.
 8. An imagereproduction laminate according to claim 1 wherein said first support isa sheet of a flexible material.
 9. An image reproduction laminateaccording to claim 1 wherein said second support is a sheet of aflexible material.
 10. An image reproduction laminate according to claim9 wherein said first support is a sheet of a flexible material.